But the North Korean statement, carried by the official KCNA news agency, said the U.S. had gone against the spirit of the summit by putting unilateral pressure on the country to abandon its nuclear weapons.

Mr Pompeo said the talks "brought us in a risky situation where we may be shaken in our unshakable will for denuclearisation, rather than consolidating trust".

"We expected the US to bring constructive measures to build confidence in accordance with the spirit of the US-NK Summit", the statement carried by state-run news agency KCNA said.

The spokesman said that the first high-level talks between the two countries following the summit failed to consolidate mutual trust, only to risk undermining the North's commitment to denuclearization.

The next line of the more than 1 200-word statement may have captured the central complaint: "The US side never mentioned the issue of establishing a peace regime on the Korean Peninsula, which is essential for defusing tension and preventing a war", an unidentified foreign ministry spokesman said.

"The statement was to my ear - in a way - much more gentle and careful than I have heard from the North Koreans on any number of occasions over two decades", Gallucci said during a call with reporters organized by 38 North, a well-respected North Korea-watching website and project of the Stimson Center, a US think tank.

In his comments to reporters before leaving Pyongyang, Pompeo said he and Kim Yong Chol had made "a great deal of progress" in some areas.

After his talks in Pyongyang, Pompeo stopped in Tokyo and met with Japanese Prime Minister Shinzo Abe and planned to brief him on his discussion with North Korean officials.

But cross-border relations have warmed after South Korean President Moon Jae-in - who has championed dialogue with the isolated North since taking office past year - held a landmark summit with the North's leader Kim Jong Un in April.

Seoul's presidential office has said the suspension of the combined exercise could facilitate ongoing nuclear talks between North Korea and the United States.

The trip was Pompeo's third to Pyongyang since April and his first since the summit.

When asked about reports that North Korea is building up sites tied to its nuclear weapons program, Pompeo insisted that Kim Jong Un is "still committed" to complete denuclearization.

That change raised suspicion that the USA was softening its demands for the country, an argument that State Department spokeswoman Heather Nauert had insisted on Friday wasn't true.

"It seems the U.S. misunderstood our goodwill and patience", the statement said.

"Thinking about those discussions you might have not slept well last night", he said to Pompeo, referencing their close to three-hour meal the night before during which they discussed "very important matters".

Pyongyang noted that it had already destroyed a nuclear test site - a concession that Trump has already publicly hailed as a victory for peace - and lamented that Pompeo had proved unwilling to match this with USA concessions.

However, he emphasized that the North still has trust in the US President, apparently hinting that Pyongyang wanted to keep the ongoing denuclearization talks on track.